The push for LED car headlamps begins...

Steen, who previously worked at General Motors, also told delegates that packaging of the LED sources is a crucial issue. He said that a "chip-on-board" concept, in which the primary optic is molded over both the LED chip and metal board (see figure), will be more suitable for car headlamps than the traditional LED package. Compared with the Luxeon package, which involves 12 parts and 13 process steps, the chip-on-board architecture requires only 5 parts and 4 processes, said Steen. This technology was developed by Global Light Industries, a German LED manufacturer acquired by Schefenacker in 2001.

Steen said that at least 13 vehicles showed an LED headlamp concept at the Detroit Auto Show in 2004. "The first-to-market race is on," he said. Each global region is actively involved in this race, while the first proposed production schedule is slated for late 2006.

http://www.ledsmagazine.com/articles/features/1/8/18

If Lumileds delivers on their announced high temperature parts and they actually work as advertised, it isn't going to matter if there is 5 steps or 20. The biggest issue in LED headlights currently is not so much the efficiency, but the overall cost, and the thermal issues which are substantial given current maximum die temperatures and the need to keep the temperature down to keep the efficiency and life up.

A simple one dollar heatpipe running across the metal skin of the body of the vehicle, with it's up to 2,000 times higher thermal conductivity than copper, can easily pull the heat out. No issues there, imho.

Been there, done that, works great. Sunlight and heat? No biggie, you don't need the massive lumens in the daytime, just running lights. Night time, no sun, very large surface, and in addition, plenty of airflow while underway.

A good general article that mentions LED headlighting.

http://www.reed-electronics.com/eb-mag/article/CA513507?pubdate=4%2F1%2F2005

Oh, there is alot of press lately on LED based headlamps.

Newbie, while pulling heat away may seem like a good idea, nothing in an automotive environment is ever $1. One of the benefits of LED lighting is packaging. If you start having really complicated thermal paths, that takes out your packaging benefits. Then there is the whole concept of reliability. Automotive designs are mean't to work in all circumstances. The issue with headlights is also heat from the engine bay as you can't be guarenteed of airflow. As you state, running lights are relatively easy as they have much lower Lumen requirements.

Visteon demos one of the industry's first "road-worthy beam pattern" applications of LED front lighting, a capability it demonstrated on the Cadillac STS SAE 100 Technology Integration Vehicle at the SAE World Congress earlier this month.

Sheppelman said that Visteon also had to overcome engineering challenges related to thermal management, for heat dissipation to withstand engine-compartment temperatures, and precise electronic current control. Visteon's LED front lighting demonstration lamps are based entirely on LED technology. Sheppelman said LED front lights are up to 55% thinner than their non-LED counterparts, thus opening up space in the engine compartment or in the grille to add styling options.

http://powerelectronics.com/autoelectronics/visteon_demos_lighting/index.html

I've made a set of LED headlights for a hybrid car that Suzuki motor vehicle has in the making. Its uses seven Lux V's. I only had access to some bad bins so I ended up using XX1T. I'll post pics and specs in a day or so. To tell you the truth, I need someone to post the pictures......... Just wanted to brag about my creation.

ARC mania

Only had access to bad bins and used XX1T? that's not a bad bin!!!

I wonder if any headlights have horizontal optics like the carlco optics. I think fraen had one too that made a beam that was like a flattened oval instead of circular light. Would be more efficient I would think and less blinding to drivers.

I see the Japanese are ahead of the US in making LED car headlamps. From Arc_Mania:

"I ended up making an LED headlamp for a
new hybrid car thats in the making by a big Japanese car maker. I wanted to
expose the headlamp pictures. I can't expose the car. The hybrid car is a
small car thats a two seater with a 660cc engine which also has an electric
motor. Anyways the headlamps use 7pcs of Lux V's from bin#XX1T driven at
700ma. I developed a boost converter to drive the LED in series. The
brightness of the unit has been tested at the car maker and it clocked in
at 1150 lumens. I have taken the photos while the headlights were in the
early stages of making and are in an un-wired state."

Hey, the lights look nice! /ubbthreads/images/graemlins/smile.gif The future looks good. Here are some of ARC_mania's pictures:

It's great to see the pics. I have lots of questions, however, I'm not sure you would be able to answer them (for confidentiality reasons). How is heat dissipation managed -is that an anodized Al part or a plastic one? What are the considerations for the relatively short life span of the Lux V?

You've done a nice job! Thanks for sharing!

Paul

Heat will be dissipated from the headlight unit to the headlight case. The headlight units are made of aluminum and HA in black.

ARC mania

Thanks ARC mania, there looks to be a nice chunk of thermal mass there.

Paul

Just think - in a few years, we can buy cheap Luxeon V replacements at the automotive section at WallyWorld

wow....

14 xbins in one location...

"Anyways the headlamps use 7pcs of Lux V's from bin #XX1T driven at 700ma."

DDDDDDDDDANG!!!!!

That's where our X-bins went! Who says the LuxV is dead? If LumiLEDs is coming out with X..T bins for cars, I bet they have a lot more tricks up their sleeve that they ain't telling us...

Gee thanks Arc mania. SO that's why i could not locate any LuxV's when I was trying to make a LuxV engine for my Mags...

P.s., what about the relaive short life span of the Lux V's? are they comparable to the Automotive H4 lamps which last a few thousand hours under intense usage?

I remember I read somewhere that the SF L4's LEDs have a much more rapid decline in out put compared to the LuxIII's, but I'm fairly certain the life is still good in automotive headlamps are concerned.

7 pieces driven at 700 ma, so that's about 5 amps total?


Now here is my question, if the 7 piece, say they make (wildly guessing) 200 lumen per piece, then it's about 1400 lumens COmpare that to a 100w bulb like Osram bulbs or Philips H4 bulbs which last about 2000 hours making 3000 bulblumens and pulling around 9 amps, the efficiency is not that much better, the life is slightly better, but then we are still looking at the problem of cost(7 pieces of LuxV's versus a 5-dollar bulb).

I personally think unless the LEDs can have much higher output to compansate the lack of throw and moisture-cutting ability, they are still not ideal for automotive usage considering the headlights of a car much be useful in ALL weather conditions...And since the holagen bulbs use relative low level of the current the battery of the internal combustion engine produces, the gain in efficiency is not worth the loss in the full spectrum light that a Holagen light bulb can provide(well, this coming from someone who dislikes HID because of the bluish tint in the HID light, it's just oh so slightly biased)...

SOrry to be the pooper at an exciting time, those things do look awsome and I hope the existing issues can be answered soon....

Nick

The push for LED headlamps is two fold:

- Packaging: LEDS will offer very flexible (and potentially very thin) packaging options. This opens up a lot of design flexibility

- Similar color to HID. While you may not like it, the cooler white light of HID with the added brightness actually gives you better depth perception and visual acuity.

You can add in, that LEDS are already about twice as efficient as Halogen in directed light applications which does add some efficiency, and long term, the cost will be less than HID.

The new Luxeons look like they will solve the heat problem, so I would expect that to be the solution as opposed to LuxV.

MJ's proto headlights are pushing the envelope.

those precious amps saved may not make much difference in an internal combustion engine, but savings would be noticed in an electrical/hybrid vehicle operating at night.